Many items of the general nature identified above have the characteristic that it is important for the item to be adjusted in position according to prevailing circumstances and, in particular, according to the time of day. In particular, adjustment of the position of the item may be necessary according to the position of the sun in the instance of solar activated items or according to the direction in which the wind is blowing in the case of a wind turbine or other wind activated machine, so that the energy source is tracked effectively.
For example, in the instance of a heliostat, the focusing of reflected solar energy accurately towards a central tower receiver is imperative and consequently the stability of the supporting structure must ensure the necessary accuracy. However, the support structures for the heliostats in such an application are responsible for an appreciable proportion of the capital expenditure on an entire installation.
In consequence of this, the development of a less costly support structure has been an ongoing challenge and one support structure that has been evolved forms the subject matter of our published international patent application WO2014072905. As shown in accompanying FIG. 1, the support structure in that instance provides a single stable pylon (A) for each heliostat (B) and the pylons are arranged in a triangular pattern with the pylons being secured together by girders (C), preferably in the form of trusses, secured to projecting plates (D) welded to the pylons and forming a framework therewith. It is considered that this arrangement will work effectively when installed on relatively even ground but may be somewhat problematical on at least some types of undulating ground. It also involves a significant amount of welding that contributes to the cost of the support structure and welds require additional corrosion protection.
It is considered that there is yet appreciable scope for improvement in an arrangement of pylons and a supporting frame for purposes such as this or for supporting any other items such as those identified above.
The preceding discussion of the background to the invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application.